Drill bit with removable blades



Aug. 3,1926. 1,594,730

J. E. HITCHCOCK DRILL BIT WITH REMOVABLE BLADES Filed Oct. 1, 1924 guy/Mz Ratented Aug. 3, 1926.

UNITED STATES- VPATENTol-I-lca JAMES E. HITCHCOCK, OF TORBANCE, CALIFORNIA.

DRILL BIT REMOVALE BLADES.

Application mea october 1, 19,24. serial Nesoesc.

My present invention is a drill bit especially suitable for use in the drilling of deep tion to providea rotary drill bit with en easily replaceable blade, which 'may beof the fish-tail type, formed of such hardmausual frequent -interruptions for resharpen--- ing; and an advantageous embodiinentof my invention may comprise abl'adefcast in" such form that its cutting edgesv 'I nay be.

sharpened or resha'rpenedby mere grinding.v A special head or retaining portion is lpreferably cast. integral'with each` blad; 'and each blade may be providedwithfmeans for engagement by a dog' or otherglatching or retaining element, whichimayfbe; seated'or housed in the co-operating bit body, which may be slotted to receive'thesame.

The usual threaded pin, associated with a fiat shoulder, being unduly liable to wear and to accidental damage, it is a further object of this invention to provide a construction obviating 'or minimizing the frequent screwing and unscrewing of threaded pins, and, in a preferred embodiment of my invention, I may employ a sliding connection between a head or expanded portion of each replaceable cast blade and a permanent bit body, the above mentioned latching element, when employed, being housed either in said blade or in said bodyr and provided with means, such' as an aperture adapted to be enga ed by a pin or' Wedge, permitting its withdrawal4 at will, or as may be requiredjfor the removal of a worn blade, to be reground or replaced.

It is a further object' o'f my invention to n provide an organization substantially above described not only witha removable terial and so designed as to assure its wear resistance and itsneiicient cutting for -long periods of time, without, necessitating the terminal blade, for `increasing the depth of a well hole, but also with a lateral blade or blades, adapted to serve as gauging cutters or reamers, eective to bring a holel to a predetermined diameter, all of the mentioned blades being advantageously thickest at the inner or securing ends thereof, Whether wedge-shaped or provided with T heads to facilitate their retention in suitable slots, and any or allof said blades may be subdivided or notched in such manner as to form interrupted cutting edges, the cutting edges left lstanding between'the mentioned staggered, in a manner favorable to their co-operativevand mutually ysupplemental action. l t

object of this invention to i It is a further notches being preferably oii's'et or relatively i provide a blade-holding bit-body with la novel arrangement of ducts and grooves for fthe efficient` circulation of a lubricating mud, or th(` like.v y

- *It is also an important general-object of this invention to provide a drilling organiza- 'tion comprising separate blades such as may actually be replaced at a cost less than the `cost of resharpening an ordinary bit, the' difference in `cutting effect and the length- Vening of the interval between withdrawals thus representing ya net gain,-which may amount to thousands of dollars saved in the sinking of a single well.

'Other objects of my invention will appear from the following description of a preferred embodiment thereof, taken in connection with the appended claims and the accompanying drawings, in which- Fig. 1 is an elevational view of my novel drillbit.`

Fig. 2 is avsubstantially median section, showing a simple type of locking device suitable for use therein.

Fig. 3 is an elevational View taken in the i direction of the arrow 3 of Fig. 1, with parts y broken away.

`Fig. 4 is a sectional view, taken as indi-` cated' by the line 4 -4 of Fig. 1. f

Referring to the details of that speciiic embodiment of my invention "chosen for purposes of illustration, 11 may be a bladeholding body, shown as comprising a shank 12 and as terminating atitsupper end in a pin 13, for the attachment of the same, an intermediate `expanded portion 14: being upwardly terminatedl by a shoulder 15,'in a usual manner.- i

Coming now to the novel features of my drill bit, the blade-holding body 11 is provided` withva transverse slot 16, shown as expanded at its upper end, to receive the correspondinglyA expanded and interfitting end 1,7 lof a removable blade 18. The blade 18 may advantageously be cast from manganese steel, or other special steel, and .initially -provided at its upper end not only with a T-shaped or similar head extending entirely thereacross but with a depression 19 therein, for engagement by a latching'dog '20, shown as provided with a spring 21, or byequivalent means, for its releasable retention within the body 11.

Although the lower end of the blade18, or its equivalent, may be provided with cutting edges of any desiredi character, I have shown this blade as oflish-tail type,

.but specialized by providingit with oppositely inclined edges 22, 23, which are interrupted by notches 24 in such manner as to leave complemental sections thereof standing; and it is obvious that the outside diameter of the blade 18, in the region of the cutting edges thereof, should substantially exceed the diameter of the supporting body 11.

Vhen a reaming effect is desired, I may optionally provide the body with additional slots or channels 25, which maybe substantially vertical and may be inwardly' expanded, as best shown in F ig. 4, in such manner as to adapt the same to the retention of lateral or reaming blades 25, the inner ends of these blades being shown as correspondingly expanded, in order to facilitate their removable retention by means such as pins or screws 26; and between the slots or channels 25 I may optionally provide additional lubricating channels 27, to which a lubricant may be delivered from a central passage 28, extending downwardly through the shank 12, by means such vas inclined ducts 29, the arrangement here referred to being such as to assure a satisfactory delivery of lubricating mud, or the like, toward both the terminal blade 18 and the lateralV or reamingblade or blades 25a.

Itwill be understood that either the terminal blade or a'pair of reaming blades may any preferred form may of course be sub- '.stitutedl for those shown, but the specific types illustrated are found to co-operate effectively for the purposes indicated.

Although 'I have herein described ,my invention in a preferred form, it will be untions may be made by those skilled in the art, without the slightest departure from the spirit and scope of myinvention, as the same is indicated above and in the following claims.

i derstood that various changes and modica- 1. In a drilling organization .adapted to l operate by 'rotation and to withstand a torque: a substantially cylindrical bladeholding body provided with lubricant sages and also with a transverse slot distinct from said passages,'whichkslot is widest at its upper end and there forms a T-shaped passage extending .entirely through said bodyv toreceive a replaceable blade; and a said head, for locking said blade in said' body.; and cam means for releasing said lock1ng..means.

msl

2. In a drilling organization adapted to I operate by rotation and to withstand a torque: a substantially cylindrical bladeholding/body provided with a transverse slot to guide a removable cam pin and with another transverse slot, the latter being widest at its upper end and there forming -a T-shaped passage extending entirely through said body to receive a' replaceable blade; a replaceable blade, havingv a cutting edge wider than said body and formed of cast metal too hard for convenient forging, said blade being provided at its inner end with an expanded head slidably intertting Within said last mentioned slot v and provided also with means permitting itsA releasable retention by a locking element; a locking element for said blade, said locking element being disengageable by means comprising a pin movable within said first mentioned slot in said bodyV and having an inclined surface adapting the same to serve as a cam.

y 3. A drill bit comprising a substantially cylindrical body provided with a T-shaped slot extending therethrough and with means for the releasable retention of a blade slidable'in said slot, and provided also with substantially vertical longitudinally extending substantially vertical external chan- Y nels in its cylindrical surface, some of said channels being adapted to retain independently removable blades, and others of said channels-being connected, by inclined ducts, With a passage for the delivery of a. lubricant thereto.-

4. A drill bit comprising a substantially cylindrical body having in its cylindrical surface substantially vertical external chnnels to receive a, lubricant, each channel 4loeing provided near its upper end with means for feeding e, lubricant thereto; and separate reaming blades supported between and 10 parallel with said channels. 1,

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 25th day of September, 1924.'v

JAMES E. HITCHCOCK. i 

